4165-57-5Relevant articles and documents
Williams et al.
, p. 5153,5154 (1967)
Entry to 1,2,3,4-Tetrasubstituted Arenes through Addressing the " Meta Constraint" in the Palladium/Norbornene Catalysis
Dong, Guangbin,Liu, Peng,Wang, Jianchun,Xu, Xiaolong,Zhou, Yun
supporting information, p. 3050 - 3059 (2020/03/10)
Arenes with four different contiguous substituents, i.e. 1,2,3,4-tetrasubstituted arenes, are commonly found in bioactive compounds, but they are nontrivial to access via conventional methods. Through addressing the "meta constraint" in the palladium/norbornene (Pd/NBE) cooperative catalysis, which is the difficulty of tolerating a sizable meta substituent in aryl halide substrates, here a modular and regioselective approach is realized for preparing 1,2,3,4-tetrasubstituted arenes. One key is the use of a C2-amide-substituted NBE, and a combined experimental and computational study reveals its role in promoting the NBE insertion and the ortho C-H metalation steps. The scope is broad: A variety of electrophiles and nucleophiles could be introduced to the ortho and ipso positions, respectively, with 1,4-disubstituted aryl halides, leading to diverse unsymmetrical contiguous tetrasubstituted arenes. Application of this approach has been demonstrated in streamlined syntheses of several bioactive compounds.
Pd(II)-Catalyzed Synthesis of Alkylidene Phthalides via a Decarbonylative Annulation Reaction
Borthakur, Somadrita,Baruah, Swagata,Sarma, Bipul,Gogoi, Sanjib
supporting information, p. 2768 - 2771 (2019/04/16)
An unprecedented Pd(II)-catalyzed decarbonylative C-H/C-C activation and annulation reaction, which proceeds via intramolecular cyclization, is reported. This reaction of hydroxynaphthoquinones with disubstituted alkynes provides good yields of substituted alkylidene phthalides, which are the key intermediates for the synthesis of bioactive natural products.
